1. Field of the Invention
The invention relates in general to a sense amplifier, and more particularly to a sense amplifier capable of reducing the feed through effect due to output signal sweeping on the reference node, which receives a reference voltage from a reference cell, of the sense amplifier.
2. Description of the Related Art
Non-volatile memory, such as flash memory, is widely used in various electronic products. Conventionally, when data stored in a memory cell of the flash is read, the memory cell is biased through a column decoder and a row decoder so that the memory cell generates a sensing current. For example, the sensing current is applied to a node for establishing a sense voltage. The sense voltage is compared with a reference voltage, which is established by a reference current provided by a reference cell, by a sense amplifier so that a sense result of the storage data can be determined.
Typically, the reference voltage is varied (or raised mostly) by the operation of the sense amplifier due to the feed through effect on an input stage circuit, which provides an internal reference current according to a reference voltage established by a reference current of the sense amplifier. What is even worse is that the reference voltage is shared by a number of sense amplifiers and the variation of the reference voltage caused by the feed through effect taking place in those sense amplifiers will be accumulated and sense results provided by those sense amplifiers will be wrongly determined. Thus, there is a prominent direction for this industry to design a sense amplifier capable of reducing the variation of the reference voltage and sensing the storage data correctly.